1. Field of the Invention
The present invention relates to a wide-angle projection lens module, and in particular relates to a wide-angle projection lens module for a short throw distance.
2. Description of the Related Art
Digital projectors have been widely used to display video or electronic generated images. Digital projectors require an appropriate display device whether used in education, home entertainment, advertising, or videoconferences.
Throw ratio is a key factor to determine an appropriate display device. In general, the term “throw ratio” can be defined as the throw distance over the picture size (i.e. picture width). Typical throw ratio of conventional projectors is about equal to 2. However, when projection size of the display device increases, the thickness thereof increases with the increased projection size. Therefore, reduced throw ratio is required for large-sized display device.